Balance Sheet Components - Additional Information (Detail) - USD ($) $ in Millions |
Sep. 30, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Research And Development Agreements [Member] | ||
| Research And Development Revenues From Collaboration Agreements [Line Items] | ||
| Deferred revenue | $ 13.2 | $ 28.9 |
| X | ||||||||||
- Definition Research and development revenues from collaboration agreements. No definition available.
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| X | ||||||||||
- Definition Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Details
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